ProMinent Softening and Demineralisation Plants About Demineralisation ProMinent Softeners and Demineralisation plants offer unique solutions for removal of total dissolved solids present in water. While hardness in water is removed by softners, Demineralisation plants are used to achieve high resistivity water. ProMinent offers softeners, De-alkalisation plants, Demineralisation plants and post Demineralisation systems.